Reverse Physiology
by Stealth Dragon
Summary: Conversion Tag. Sheppard heals. CarsonJohn friendship.


**Reverse Physiology**

by

Stealth Dragon

Rating: K+

Disclaimer: I do not own Stargate Atlantis.

Summary: Sheppard recovers, but not alone. Tag for Conversion. I took a bit of creative licensing with just how far John's body had transformed, had what might have developed that we didn't see.

A/N: This story has been in my head for a while and it was only a matter of time before I got it written down. Thanks to Kristen999 for the motivation.

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"The patient has begun to exhibit reactions antithesis to the side affects of his transformation: namely an acute awareness to pain. I was correct in my theory that during reversal, the natural pain inhibitors would be the first to go. The exoskeleton should follow soon after. It is already showing signs: dryness, cracks, flaking. Much like shedding skin. The body will either absorb it or reject it."

Carson clicked off the recorder and exchanged it for the PC tablet the nurse had been holding for him.

"Temperature?" he asked.

"Still at ninety-nine," she said. Fahrenheit, Celsius: Carson could work with both.

He moved closer to the bed where Colonel Sheppard was curled like a pup, figuratively dead to the world beneath knit blankets. There was no longer a need for restraints or keeping him in a medically induced coma. The reverse of his transformation was leaving him weaker than a newborn.

It felt almost like spite that the strength, stamina and natural painkillers were the first lost. Stripped, actually, like a car in a chop-shop, taking away more than it had given. It had forced the use a feeding tube to pump liquid nutrients into Sheppard's flaccid stomach, and a vitamin regime by I.V. to make up the difference.

The nurse pulled the blankets to John's waist for Carson to pull the scrub up to his neck. Sheppard shifted as though about to roll onto his back, flashing pale blue stomach and an armored chest. A gentle prod to the back kept him on his side. Carson pressed his thumb into the middle ridge overlapping, like panels, each individual rib, and wriggled it.

Even botched nature was remarkably accommodating. Layering protected the ribcage while allowing it to still expand. There was usually a little give when Beckett pressed. Today, it was more pronounced. Carson followed its curve to the plates over the spine, overlapped like the ribs, with a skin-crawling surprise beneath the tear-shaped layers. Carson lifted a scale that slid a needle-thin appendage, like a straightened cat's claw, out of hiding. He was happy, and a little relieved, to see it bone white and brittle rather than liquid clear and dripping. The venom in the spines wasn't so much a venom as a paralyzing agent, temporary of course. Considering what John had been turning into, it made sense not to want its... his... attacker – prey – dead.

Carson still had yet to determine how Sheppard would have fed when the transformation was complete. There had been no slit in the hand, not even a line indicating where a slit would form.

John's back arched away from the manipulation.

"S-s-stooop." It wasn't a plaintive demand, it was a frightened plea.

Carson released the scale, even smoothing it over until Sheppard's body relaxed. "Sorry lad. Sorry."

He really didn't give a damn how Sheppard would have fed.

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Teyla was a saintly lass with the understanding that was needed when it came to visiting John. Sheppard had his ups and downs with his sensitivity levels. He never opened his eyes no matter how dimmed the lights. Maybe a squint long enough to reorient him, but that was it. Yet he would always open them the moment Teyla took his hand into hers. Most days, he was too drugged to care about the contact. The days that he wasn't, he would pull away, and Teyla would let him.

Today, as she held one hand, his other hand reached out trailing a chipped claw down her cheek. Teyla stiffened in alarm, and Carson moved to intercept. There was no saying when an act of... Carson wasn't sure what to call what John was doing. Curiosity? Affection?... would turn into aggression, and awake didn't equal aware, not with the amount of medication running thick in John's bloodstream. Plenty enough reason not to take chances.

A minute shake of Teyla's head and a reassuring look stopped him. Sheppard's one finger caressed her face over and over, four times, when it stopped.

Carson finally realized that John's eyes were open, reptile pupils narrowed to slivers. They moved from Teyla to the blue hand, widened, then slammed shut. Sheppard turned away, curling into himself as though trying to shrink out of existence.

Carson thought for sure Teyla was going to cry. Instead, she reached out to rub his arm, speaking too low for anyone but Sheppard to hear.

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It was tricky maintaining a workable schedule for administering pain medication. The reconstruction of John's body had his metabolism, his body chemistry in general, skirting the edge of chaos without any real rhythm to keep to. The slowest the medication had been metabolized was two days, and the fastest thirty minutes. Not even putting him back into a coma lasted long.

Without the natural painkillers, Sheppard's body would have felt every molecular change, and Carson didn't want to even imagine the agony involved. Even with administered medications, the moment there was a lull in the affects, Sheppard would start whimpering and thrashing. The frail helplessness alone, so unnatural for John, was hard enough to take.

Carson sometimes thought himself a selfish bastard. Sheppard squirmed and moaned and begged with alien eyes looking pathetically large and sunken in his skull. He was staring at Carson, silently pleading for help, sensitivity to light be damned because everything else hurt a hell of a lot more.

Beckett filled the syringe with the recommended amount and injected it into the I.V. He made the mistake of meeting those mutated eyes, saw the begging morph into muted thanks as the pain was washed away.

Carson almost ran. As it was, he could barely stop his hand from shaking. Wasn't he the reason for Sheppard's pain? And here the man was, half-human, deteriorated, helpless and looking at Beckett with insane amounts of gratitude for the temporary reprieve.

Carson wanted to be pissed at him. Why couldn't Sheppard just hate him? Blame him? Give him what he deserved? Yes, they'd gone over it, it was an accident, and Sheppard would say Beckett was the reason he was still alive. That didn't matter. It didn't absolve the fact that Carson had been too damn anxious about taking advantage of an opportunity to consider all the risks.

Ga, he felt like bloody Frankenstein! Maybe his mistake was, thankfully, alive and kicking, but it had still resulted in a hell of a mess.

Sheppard didn't simply have a right to be mad at Carson, he needed to be mad. There needed to be punishment, retribution, _something_. You don't play God without getting nipped in the arse for it, and Beckett had quite a pound of flesh to give.

John's blue eyelids slid back over the mutated eyes. Carson didn't allow himself a sigh of relief. Maybe Sheppard's forgiveness was punishment enough, because it's what Carson didn't want, and it hurt far more than blame.

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Rodney was amusing and admirable in his forced loyalty, always stepping into the isolation room like a man heading for the guillotine: stiff, slow, pushing resolve to the surface though it never quite reached his eyes. A martyr doing what needed to be done for the good of all.

More simply, doing what team-members were supposed to do. Teyla and Ronon visited individually, so it was only good and proper that Rodney should as well. Carson suspected a little prodding involved, maybe on Teyla's or Ronon's part. McKay could talk about responsibility and there being no I in team all he wanted; the man had a kinship with the Colonel you'd have to be a blind idiot not to see. Carson saw it every time McKay reached the bed, pausing just before he sat. It was the same every visit: Rodney would lean forward, craning his neck for a peek at Sheppard's face. Maybe it was the vulnerability, the lines of stress, how thin the Colonel looked, how small he seemed curled up as he was – McKay's features would always phase through the same cornucopia of expressions: alarm, consideration, worry, sorrow, until composing into the schooled mask he wore every day. He would then sit and talk for hours about the mundane, or work on something on his laptop.

"He looks worse," Rodney said before he started typing.

Carson didn't look up from picking at the scales on Sheppard's wrist. They came away in flakes the size of his pinky, crumbling to blue dust when he pressed them between his thumb and forefinger. It explained why the sheets looked like they'd been smeared with blue chalk.

"Considering what his body is going through." Carson had explained it all before as best he could. Things were to get worse before they got better. "At least the scaling's starting to clear up."

McKay muttered something sarcastic about Halloween costumes, and continued typing. Beckett looked at him, watching the physicist's concentration split between the screen and glancing at John.

Carson lowered John's wrist back to the bed. "He's not going anywhere, Rodney."

McKay stopped typing but didn't look away. He was silent for the longest Carson had ever heard... or not heard.

"I know," Rodney finally said, then he resumed.

Carson lowered his head to hide his smile as he picked up Sheppard's other wrist.

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Some of the scaling was being absorbed, some of it flaking away in chips and fine dust. They had to put a mask over Sheppard's mouth and nose to keep him from breathing it in. It also became protocol to do the same for one's self. John's shifting and rolling was turning the armor into a fine, misty powder. The last thing John needed was pneumonia, and the last thing Atlantis needed was for anyone else to mutate.

Carson's bigger concern was the Colonel's bones always showing up near-transparent on the X-rays and scans. It was suspected that all calcium had gone into developing the scales, and it made sense. The creation of an exoskeleton would make an internal skeleton obsolete. How obsolete, no one could say. The armor would have made it possible for John to live without a solid ribcage or skull, maybe even the bones of the arms and legs if the outer shell became hard enough. Except that still left the spinal column. Carson just couldn't see such a support system developing outside the body strong enough to uphold that body, though the entomologists insisted it was possible. So far, the backbone was the only part of the skeleton still bright white, and either would have remained that way or would have been the last bone to go.

Again, Carson didn't care. He was just happy that they didn't have to worry about John inadvertently snapping his own neck.

That still left the rest of his bones.

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Carson sometimes preferred Ronon's visits. He was far from being uncomfortable when asked to help and, selfish as it was, didn't ooze with concern and sympathy when he did. Nothing against Teyla, it was just... hard, sometimes, seeing the sorrow that interchanged with the compassion in her eyes.

Ronon simply was, ready to do what needed to be done and eager to do it.

Today, however, Beckett felt more apprehension than gratitude, what with the condition of John's skeleton and all. It was bath day, and they needed to be able to get to every inch of Sheppard's upper body. The scales were coming off in larger chunks to be crushed into more powder under John's weight, and some of the shards were pricking the more vulnerable patches of skin.

"You need to be careful," Carson said, squeezing liquid soup into the last bowl. "Especially around his chest. His ribs are fragile." More like elastic; like cartilage, actually, with too much give at the slightest pressure. With the armor going brittle, responsibility for protecting the chest cavity had gone back to the ribs, and they weren't ready. It was why Sheppard had stopped curling onto his side, and why he had trouble breathing until he slid his arm from its resting spot below his sternum.

Ronon nodded. "Okay."

It was amazing how gentle that big man could be. Carson had to wonder if he'd ever worked in a hospital, maybe volunteered. Ronon's movements were slow, almost smooth, as he slid onto the bed while maneuvering Sheppard up against his chest. He kept his hands on John's shoulders and the pilot's head resting against his collarbone as a nurse cut away the scrub.

While the nurses wiped flaking scales and dust, Ronon idly pick chitinous from John's elbow. The armor was soft when wet, like bark after a rain. It pulled away, easy and malleable as clay, from pale blue skin marked in raw patches. They had to move slow and light, keep from tearing away scaling that wasn't ready to come off yet. If that happened, then John would bleed.

Against the light blue was the darker blue of tiny veins and thinner red capillaries, like webbing. Sheppard's skin would be transparently pale when the blue finally cleared up. It looked thin, like tissue paper, and it unnerved Carson every time scale was peeled away. No clinical professionalism could stop the fear of tearing that skin and causing Sheppard more pain.

When they wiped away all that they could, they dried Sheppard and cautiously dressed him. With the same gentle care, Ronon lowered him back onto the bed and covered him up.

Carson highly doubted Sheppard had been aware of any of it. He had yet to be. Or, at least, had yet to give Beckett any reason to believe so.

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The scaling was fading in reverse of how it had developed, and the blue was going with it. Pale flesh was creeping higher, from John's stomach to his sternum, and spreading radial. That still left his hands, arms and head. The nurses had to file the claws using a metal emery board to keep John from gouging himself or anyone who startled him.

There was still sensitivity, not so much to sound, though. Still to light and most definitely to touch. They had to talk him awake before touching him or he would start with violent flails and jerks that had given more than one nurse a black eye. Carson had his own bruises, both along his jaw, and nicks from where the spines of the hand had caught him. The only positive to the armor was that it kept the bones of John's hand intact.

The reactions were far from Sheppard's fault, who was too out of it to know what he was doing. He was beginning to show signs of decreased pain: discomfort that had him moaning rather than thrashing and whimpering. He was also waking more; less comatose and more lethargic and groggy, but still with enough awareness to answer a few questions clearly.

As well as ask his own questions, more than once, usually wondering if everyone was okay (he kept forgetting dates, asking about missions from months ago, even asking after Ford). Whether the answer was a yes or no, Sheppard never had enough energy to think it over, and would go right back to sleep.

Carson still considered getting him alert enough to swallow a cup of broth. The Colonel needed to set his feet back onto the road to solids at some point. An uncomfortable amount of muscle tone had been lost, and the majority of the pilot's lethargy was from natural weakness, not the sedatives.

Beckett forced himself to wait another three days before decreasing the relaxants and coaxing Sheppard awake vocally... and at a safe distance. When John stirred, fluttering languid eyelids, Carson moved carefully forward.

"You with us, lad?"

Sheppard mumbled incoherently, lifting a shaking clawed hand to rub his face.

"I need you to drink as much as you can of this," Carson said, raising the head of the bed, then bringing the cup's straw within reach. He managed five swallows – not too bad – before giving up and blinking his way back to sleep.

Beckett went back to the table to record the change. Real progress would be Sheppard finishing the broth off, but each extra swallow was just as important. Rome wasn't built in a day, and neither were appetites.

A strangled cry, strained by weakness but deafening in the silence, startled Carson. He whipped around to see John, eyes wide open, one alien and one human, staring at the ceiling as his chest billowed too fast to take in enough air.

"Bloody hell!" Carson hissed, hurrying over to grab the hands trying to push the weak body up. "Colonel. Colonel Sheppard? John!"

John's hands lurched forward digging claws into the lapels of Carson's lab coat. Strength born of fear made it possible for Sheppard to pull himself up centimeters from the bed, forcing Carson to lean in before the man's arms gave out. With inches between them, it was impossible to look away from the eyes both terrified and pleading. Beckett didn't think, he just reached out, one hand gripping John's wrist and the other brushing through his hair. It seemed as natural as breathing to use touch to comfort, and Sheppard didn't pull away.

"Is... is she... Did I," Sheppard panted. "Please, please tell me I didn't... I didn't... kill her. Please."

"Who, lad?"

"L -Liz-beth. My hand... damn it, I was choking her! Oh, gosh, please tell me, please..." and then he broke, releasing Carson to shrivel into a huddle as he sobbed and shuddered. Beckett continued his ministrations, swallowing back the choking lump in his throat.

"No. No, of course not, son. She's alive and well. You barely even left any bruising..." he winced, wanting to kick himself for that one. He released John's wrist in order to rub his arm. "It's all right, lad. She's safe. You didn't kill anyone. You fought it too good for it to end like that."

With a hiccup, John lifted his head. Wet traces glittered on the few scales still clinging like dead leaves to his face. "She's all right?"

"Aye, she's perfectly fine. You didn't hurt her."

John nodded as relief melted him. Then his eyes bulged. "Crap... sick!"

Carson had no time to so much as step back when John lurched forward gagging up the five swallows of broth all over the doctor's shoes.

"Sorry," John moaned, slumping.

Sighing, Carson patted his shoulder. "Don't worry about it."

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It was two days before Carson risked giving John any more broth, followed by five days when he felt John ready to handle something more solid. The reversal was nearing completion, the scaling almost gone except from one hand. His bones were stronger, making it possible for him to sleep more on his side as well as sit up.

Carson had left Elizabeth with John while he fetched food. He returned to find her still there, talking softly to a distressed looking Sheppard. Beckett's immediate desire was to set the tray aside and rush in to ensure Sheppard wasn't having another panic attack. He took one step into the isolation room when Elizabeth and Shepard suddenly embraced.

Carson's next reaction was to back-peddle, just enough not to be seen while still able to see for himself. He was no voyeur, and found no pleasure in being a busy body looking to spawn gossip. But the leader of the expedition and the leader of the military hugging so freely, without Sheppard's usual awkwardness, was too much of an oddity to pull away from so easily.

It was Sheppard's sobbing, his constant apologizing in a tone that sounded more like begging, that forced Beckett to turn away. There was no intimacy of the kind that could get two leaders into trouble, here. Mere comfort was all, something John had been needing far more than pain medication and calcium now that he was starting to remember details. For all the control he'd managed to scrape up since his increased awareness, it was a drop compared to his usual control. He was like an open wound, raw and exposed, taking little provocation to start bleeding.

Carson remained hovering the entire time, making sure no one walked in on the scene, because people saw what they wanted and neither leader needed that kind of exposure; John especially.

Only when it was over did he walk in, pleased to see a tired smile on the Colonel's pale face.

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Sheppard, always the most eager out of anyone for normalcy, jumped on everything and anything Carson offered that would get him back to his feet sooner.

Not just his feet, but back to the way he was.

Getting up, moving about, walks, weights and a heavy intake of calcium – all taking place in the infirmary since there was still so much to keep an eye on. John's body was finally starting to settle back into normal human rhythms, but with enough remaining glitches (weakened immune system, heart palpitations and muscles spasms to name a few) to keep Carson cautiously optimistic. John would be released when he was one hundred percent John, not eighty or ninety percent.

In the meantime, building muscle and bone-mass was what kept John blissfully occupied.

It was when the glitches stopped popping up and John's DNA read perfectly human that Carson had no choice but to release him. Liberation day was supposed to be a happy occasion for both parties. The catch was paranoia.

What if it all wasn't permanent? What if, as soon as the treatment ended, Sheppard reverted? What if, hidden too small and tangled within John's DNA, the insect slept?

Science would say to keep that in mind, because you never know. Except it wasn't about science, it was about mistakes, and setting wrongs to right. It was about making sure John never went through that again.

So, for that reason, Carson had him stick around a few more days, just to play it safe. Five days, exactly, when it became irrefutable that John would remain John. Sheppard could also be a right bloody pain when he thought Carson was being unreasonably careful. Whine, charm, toss in some logic – the man was relentless. Beckett couldn't decide if it was the proof or the cajoling that finally cracked him.

"You're sadistic with your compassion, doc," John said, slipping into the blue-button shirt like it was a jacket. "Not that I don't appreciate it, mind you. It's just that a guy can go insane looking at the same walls for weeks." He had a leaner look, all wiry muscles and hard angles, like something wild. Time out on the nearest balcony during warm days had given his skin enough color not seem so washed out. And except for the scar on his arm that would eventually clear up, there wasn't a trace of blue to be found save for the natural blue-violet of his veins.

Even his chest hair had grown back.

Carson smirked as he waited for Sheppard to finish dressing. "I apologize for nearly driving you insane, but I don't apologize for being a cautious bastard. Now, remember, you take it easy. Lots of calcium and vitamin C, and you come back if you experience anything out of the ordinary. That includes headaches."

John finished maneuvering the last button through the hole. "Headache's kind of a given, doc. I hate those." The shirt had been the last article of clothing to go on his body. When he finished, he straightened it out, smoothing and tugging, over and over like busy work. It was hard to miss the not-so-subtle shift from anxious-for-freedom to awkward and trying to hide it.

Carson didn't say anything since he knew better. John Sheppard wasn't a man you prodded and provoked into talking when you wanted him to, not unless you were trying to get rid of him. He wasn't a man you came to, but a man who came to you, which sometimes required time and a little patience.

Sheppard finally stopped fussing to shove his hands into his jean's pockets. He kept his head down as he watched his own foot scuff the floor with its heel.

"Thanks, doc," he said, and cleared his throat. "For um... for everything you did. For, you know, saving me, of course. But also for everything else."

Carson arched his eyebrows. "You remember much of it?"

John shrugged. "Fragments. I knew it was uncomfortable as hell and... I knew I wasn't alone and stuff. That helped a lot."

Carson nodded, gnawing his bottom lip until he managed to shove back the familiar fury over what he didn't deserve. "I'm sorry Colonel..."

John's head shot up, eyes flashing like hazel steel. "Don't. Carson, just... just don't okay? We've already been through this. I don't blame you."

"But..."

"No, Carson... crap!" Sheppard rubbed the back of his head, brow furrowed in deep concentration. After less than a minute, he shook his head. "I don't want you beating yourself up over this."

Carson's throat tightened until he couldn't speak, so had no choice but to hear John out.

"You risked your ass to save me," John said. "A guy who goes that far to right what he thought he did wrong shouldn't have any reason to keep beating himself up. Seriously, Carson, just accept the fact that you made things right, I've forgiven you, and move on. You lived and you learned, so there's not much being pissed at yourself is going to accomplish." He looked up, locking his eyes with Beckett's. Blemishing the hardened steel meant to make Carson quail were flecks of pleading and concern. "You good, doc?"

It was impossible not to smile, even if it came across as rueful. "No," Carson answered honestly. "Doesn't mean I won't be, eventually, though."

John smiled back, moving forward to clasp Carson on the shoulder. "Glad to hear it." Then he left.

As soon as Sheppard was beyond sight, Carson headed to the table littered with laptops, syringes, tubes, wires and microscopes. Grabbing the recorder, he clicked it on and stared at it. Clinical diagnoses in technical terms ran like a ticker-tape through his head, long-winded and excessively intelligent.

Beckett cleared his throat. "The patient is alive and well." Then he switched it off.

The end

A/N: There's probably a lot I didn't take into consideration concerning John's transformation (I debated over the scientists debating over whether John would remain upright or go to all fours, as well as go into why the Wraith ended up with their current physiology rather than something more insect-like). But I didn't want to make things overly complicated or start a debate. The story isn't about what John had almost become, it's about healing. The rest is just my personal take on the details of his transformation.


End file.
